Method and device for paging in sidelink communication

ABSTRACT

A method for paging in sidelink communication include the steps of: receiving window configuration information from a base station; performing a first resource sensing operation for transmission of a paging message within A window indicated by the window configuration information to determine P candidate resources; performing an operation of selecting a P transmission resource from among the P candidate resources within B window indicated by the window configuration information, and a second resource sensing operation for transmission of data associated with the paging message; and transmitting the paging message to a receiving terminal by use of the P transmission resource.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation-in-part of currently pendingInternational Patent Application No. PCT/KR2021/017109, filed Nov. 19,2021, which claims priority to Korean Patent Application Number10-2021-0160201, filed Nov. 19, 2021, and U.S. Provisional PatentApplication No. 63/116,331, filed Nov. 20, 2020, the entire contents ofwhich are incorporated herein for all purposes by these references

BACKGROUND OF THE PRESENT DISCLOSURE Field of the Present Disclosure

The present disclosure relates to a sidelink communication technique,and more particularly, to a technique for resource sensing and selectionfor transmission of a paging message.

Description of Related art

A Fifth-Generation (5G) communication system (e.g., New Radio (NR)communication system) which utilizes a frequency band higher than afrequency band of a Fourth-Generation (4G) communication system (e.g.,Long Term Evolution (LTE) communication system or LTE-Advanced (LTE-A)communication system) as well as the frequency band of the 4Gcommunication system has been considered for processing of wirelessdata. The 5G communication system can support Enhanced Mobile Broadband(eMBB) communications, Ultra-Reliable and Low-Latency communications(URLLC), massive Machine Type Communications (mMTC), and the like.

The 4G communication system and 5G communication system can supportVehicle-to-Everything (V2X) communications. The V2X communicationssupported in a cellular communication system, such as the 4Gcommunication system, the 5G communication system, and the like, may bereferred to as “Cellular-V2X (C-V2X) communications.” The V2Xcommunications (e.g., C-V2X communications) may includeVehicle-to-Vehicle (V2V) communications, Vehicle-to-Infrastructure (V2I)communications, Vehicle-to-Pedestrian (V2P) communication,Vehicle-to-Network (V2N) communication, and the like.

In the cellular communication systems, the V2X communications (e.g.,C-V2X communications) may be performed based on sidelink communicationtechnologies (e.g., Proximity-based Services (ProSe) communicationtechnology, Device-to-Device (D2D) communication technology, or thelike). For example, sidelink channels for vehicles participating in V2Vcommunications may be established, and communications between thevehicles may be performed using the sidelink channels. Sidelinkcommunication may be performed using configured grant (CG) resources.The CG resources may be periodically configured, and periodic data(e.g., periodic sidelink data) may be transmitted using the CGresources.

Meanwhile, when a resource allocation (RA) mode 2 is used, it isnecessary to configure a sidelink resource for transmitting a pagingmessage and/or a wake-up signal. When a paging message and/or a wake-upsignal is transmitted in a preconfigured sidelink resource withoutconsidering a current resource occupancy state, a collision may occur intransmission of the paging message and/or the wake-up signal. In theinstant case, energy efficiency and reception performance in sidelinkcommunication may deteriorate.

The information included in this Background of the present disclosure isonly for enhancement of understanding of the general background of thepresent disclosure and may not be taken as an acknowledgement or anyform of suggestion that this information forms the prior art alreadyknown to a person skilled in the art.

BRIEF SUMMARY

Various aspects of the present disclosure are directed to providing amethod and an apparatus for transmission of a paging message in sidelinkcommunication.

A method of a transmitting terminal, according to various exemplaryembodiments of the present disclosure for achieving the above-describedobjective, may include: receiving window configuration information froma base station; determining paging (P) candidate resources by performinga first resource sensing operation for transmission of a paging messagewithin an A window indicated by the window configuration information;selecting a P transmission resource from among the P candidate resourceswithin a B window indicated by the window configuration information, andperforming a second resource sensing operation for transmission of dataassociated with the paging message; and transmitting the paging messageto a receiving terminal using the P transmission resource.

The operation method may further include: selecting a data (D)transmission resource from among D candidate resources within a C windowindicated by the window configuration information; and transmitting thedata to the receiving terminal using the D transmission resource,wherein the D candidate resources are determined by the second resourcesensing operation.

The A window, the B window, and the C window may be configuredindependently of each other.

The window configuration information may include time resourceinformation of the A window, time resource information of the B window,and time resource information of the C window.

A first window interval may be configured between the A window and the Bwindow, a second window interval may be configured between the B windowand the C window, and time resource information of the first windowinterval and time resource information of the second window interval maybe included in the window configuration information.

The window configuration information may be configured for each resourcepool, and first window configuration information and second windowconfiguration information may be configured for one resource pool.

One window configuration information among the first windowconfiguration information and the second window configurationinformation may be used, and the one window configuration informationmay be determined according to a condition based on at least one of asize of transmission data, a required latency, a priority per data, or apriority per sidelink service.

The operation method may further include: when the first resourcesensing operation is completed before a reference time configured by thebase station, early terminating the A window.

The B window may start at an early termination time of the A window or atime after a window interval from the early termination time of the Awindow.

The A window may be early terminated when one or more conditions aresatisfied, and the one or more conditions may be determined based on atleast one of a size of transmission data, a required latency, a priorityper data, or a priority per sidelink service.

When an early termination operation of the A window is enabled by thebase station, the window may be early terminated.

A method of a transmitting terminal, according to various exemplaryembodiments of the present disclosure for achieving the above-describedobjective, may include: receiving window configuration information froma base station; performing a first resource sensing operation fortransmission of a paging message and a second resource sensing operationfor transmission of data associated with the paging message within awindow #1 indicated by the window configuration information; selecting apaging (P) transmission resource from P candidate resources determinedby the first resource sensing operation within a window #2 indicated bythe window configuration information; selecting a data (D) transmissionresource from D candidate resources determined by the second resourcesensing operation within the window #2; transmitting the paging messageto a receiving terminal in the P transmission resource; and transmittingthe data to the receiving terminal in the D transmission resource.

When the first resource sensing operation and the second resourcesensing operation are completed before a first reference time configuredby the base station, the window #1 may be terminated early.

The window #2 may start at an early termination time of the window #1 ora time after a window interval from the early termination time of thewindow #1.

The window #1 may be early terminated when one or more conditions aresatisfied, and the one or more conditions may be determined based on atleast one of a size of transmission data, a required latency, a priorityper data, or a priority per sidelink service.

When at least one operation of the first resource sensing operation andthe second resource sensing operation is not completed within a secondreference time configured by the base station, the window #1 may bereconfigured, and the at least one operation may be performed within thereconfigured window #1.

The reconfigured window #1 may start from the second reference time or atime after an offset configured by the base station from the secondreference time.

The window configuration information may include time resourceinformation of the window #1 and time resource information of the window#2, and the window #1 and the window #2 may be configured independentlyof each other.

The window configuration information may be configured for each resourcepool, and first window configuration information and second windowconfiguration information may be configured for one resource pool.

One window configuration information among the first windowconfiguration information and the second window configurationinformation may be used, and the one window configuration informationmay be determined according to a condition based on at least one of asize of transmission data, a required latency, a priority per data, or apriority per sidelink service.

According to an exemplary embodiment of the present disclosure, a window(e.g., a resource sensing window and/or a resource selection window) fora paging procedure in a sidelink may be configured independently. Forexample, a transmitting terminal may perform a resource sensingoperation for paging message transmission in an A window, may perform aresource selection operation for paging message transmission and aresource sensing operation for data transmission in a B window, and mayperform a resource selection operation for data transmission in a Cwindow. Accordingly, a transmission collision of a paging message insidelink communication may be prevented. Furthermore, the window may beterminated early, and thus the efficiency of using sidelink resourcesmay be improved. Furthermore, the window may be reconfigured, andaccordingly, a transmission success probability of the paging messagemay be improved.

The methods and apparatuses of the present disclosure have otherfeatures and advantages which will be apparent from or are set forth inmore detail in the accompanying drawings, which are incorporated herein,and the following Detailed Description, which together serve to explaincertain principles of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram illustrating V2X communication scenarios.

FIG. 2 is a conceptual diagram illustrating an exemplary embodiment of acellular communication system.

FIG. 3 is a conceptual diagram illustrating an exemplary embodiment of acommunication node forming a cellular communication system.

FIG. 4 is a block diagram illustrating an exemplary embodiment of a userplane protocol stack of a UE performing sidelink communication.

FIG. 5 is a block diagram illustrating a first exemplary embodiment of acontrol plane protocol stack of a UE performing sidelink communication.

FIG. 6 is a block diagram illustrating a second exemplary embodiment ofa control plane protocol stack of a UE performing sidelinkcommunication.

FIG. 7 is a sequence chart illustrating a first exemplary embodiment ofa method for transmitting and receiving data according to a pagingprocedure in sidelink communication.

FIG. 8 is a conceptual diagram illustrating a first exemplary embodimentof windows for a resource sensing operation and/or a resource selectionoperation in sidelink communication.

FIG. 9 is a conceptual diagram illustrating a second exemplaryembodiment of windows for a resource sensing operation and/or a resourceselection operation in sidelink communication.

FIG. 10 is a conceptual diagram illustrating a third exemplaryembodiment of windows for a resource sensing operation and/or a resourceselection operation in sidelink communication.

FIG. 11 is a conceptual diagram illustrating a fourth exemplaryembodiment of windows for a resource sensing operation and/or a resourceselection operation in sidelink communication.

FIG. 12 is a conceptual diagram illustrating a fifth exemplaryembodiment of windows for a resource sensing operation and/or a resourceselection operation in sidelink communication.

FIG. 13 is a conceptual diagram illustrating a sixth exemplaryembodiment of windows for a resource sensing operation and/or a resourceselection operation in sidelink communication.

It may be understood that the appended drawings are not necessarily toscale, presenting a somewhat simplified representation of variousfeatures illustrative of the basic principles of the present disclosure.The specific design features of the present disclosure as includedherein, including, for example, specific dimensions, orientations,locations, and shapes will be determined in part by the particularlyintended application and use environment.

In the figures, reference numbers refer to the same or equivalent partsof the present disclosure throughout the several figures of the drawing.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of thepresent disclosure(s), examples of which are illustrated in theaccompanying drawings and described below. While the presentdisclosure(s) will be described in conjunction with exemplaryembodiments of the present disclosure, it will be understood that thepresent description is not intended to limit the present disclosure(s)to those exemplary embodiments of the present disclosure. On the otherhand, the present disclosure(s) is/are intended to cover not only theexemplary embodiments of the present disclosure, but also variousalternatives, modifications, equivalents and other embodiments, whichmay be included within the spirit and scope of the present disclosure asdefined by the appended claims.

Because the present disclosure may be variously modified and haveseveral forms, specific exemplary embodiments will be shown in theaccompanying drawings and be described in detail in the detaileddescription. It should be understood, however, that it is not intendedto limit the present disclosure to the specific exemplary embodimentsbut, on the other hand, the present disclosure is to cover allmodifications and alternatives falling within the spirit and scope ofthe present disclosure.

Relational terms such as first, second, and the like may be used fordescribing various elements, but the elements should not be limited bythe terms. These terms are only used to distinguish one element fromanother. For example, a first component may be named a second componentwithout departing from the scope of the present disclosure, and thesecond component may also be similarly named the first component. Theterm “and/or” means any one or a combination of a plurality of relatedand described items.

In exemplary embodiments of the present disclosure, “at least one of Aand B” may refer to “at least one of A or B” or “at least one ofcombinations of one or more of A and B”. In addition, “one or more of Aand B” may refer to “one or more of A or B” or “one or more ofcombinations of one or more of A and B”.

In exemplary embodiments of the present disclosure, ‘(re)transmission’may refer to ‘transmission’, ‘retransmission’, or ‘transmission andretransmission’, ‘(re)configuration’ may refer to ‘configuration’,‘reconfiguration’, or ‘configuration and reconfiguration’,‘(re)connection’ may refer to ‘connection’, ‘reconnection’, or‘connection and reconnection’, and ‘(re)access’ may refer to ‘access’,‘re-access’, or ‘access and re-access’.

When it is mentioned that a certain component is “coupled with” or“connected with” another component, it should be understood that thecertain component is directly “coupled with” or “connected with” to theother component or a further component may be disposed therebetween. Incontrast, when it is mentioned that a certain component is “directlycoupled with” or “directly connected with” another component, it will beunderstood that a further component is not disposed therebetween.

The terms used in an exemplary embodiment of the present disclosure areonly used to describe specific exemplary embodiments of the presentdisclosure, and are not intended to limit the present disclosure. Thesingular expression includes the plural expression unless the contextclearly dictates otherwise. In an exemplary embodiment of the presentdisclosure, terms such as ‘comprise’ or ‘have’ are intended to designatethat a feature, number, step, operation, component, part, or combinationthereof described in the specification exists, but it should beunderstood that the terms do not preclude existence or addition of oneor more features, numbers, steps, operations, components, parts, orcombinations thereof

Unless otherwise defined, all terms (including technical and scientificterms) used herein include same meaning as commonly understood by one ofordinary skill in the art to which the present disclosure belongs. Termsthat are generally used and have been in dictionaries should beconstrued as having meanings matched with contextual meanings in theart. In the present description, unless defined clearly, terms are notnecessarily construed as having formal meanings.

Hereinafter, forms of the present disclosure will be described in detailwith reference to the accompanying drawings. In describing the presentdisclosure, to facilitate the entire understanding of the presentdisclosure, like numbers refer to like elements throughout thedescription of the figures and the repetitive description thereof willbe omitted.

FIG. 1 is a conceptual diagram illustrating V2X communication scenarios.

As shown in FIG. 1 , the V2X communications may includeVehicle-to-Vehicle (V2V) communications, Vehicle-to-Infrastructure (V21)communications, Vehicle-to-Pedestrian (V2P) communications,Vehicle-to-Network (V2N) communications, and the like. The V2Xcommunications may be supported by a cellular communication system(e.g., a cellular communication system 140), and the V2X communicationssupported by the cellular communication system 140 may be referred to as“Cellular-V2X (C-V2X) communications.” Here, the cellular communicationsystem 140 may include the 4G communication system (e.g., LTEcommunication system or LTE-A communication system), the 5Gcommunication system (e.g., NR communication system), and the like.

The V2V communications may include communications between a firstvehicle 100 (e.g., a communication node located in the vehicle 100) anda second vehicle 110 (e.g., a communication node located in the vehicle110). Various driving information such as velocity, heading, time,position, and the like may be exchanged between the vehicles 100 and 110through the V2V communications. For example, autonomous driving (e.g.,platooning) may be supported based on the driving information exchangedthrough the V2V communications. The V2V communications supported in thecellular communication system 140 may be performed based on “sidelink”communication technologies (e.g., ProSe and D2D communicationtechnologies, and the like). In the instant case, the communicationsbetween the vehicles 100 and 110 may be performed using at least onesidelink channel established between the vehicles 100 and 110.

The V2I communications may include communications between the firstvehicle 100 (e.g., the communication node located in the vehicle 100)and an infrastructure (e.g., road side unit (RSU)) 120 located on aroadside. The infrastructure 120 may also include a traffic light or astreet light which is located on the roadside. For example, when the V2Icommunications are performed, the communications may be performedbetween the communication node located in the first vehicle 100 and acommunication node located in a traffic light. Traffic information,driving information, and the like may be exchanged between the firstvehicle 100 and the infrastructure 120 through the V2I communications.The V2I communications supported in the cellular communication system140 may also be performed based on sidelink communication technologies(e.g., ProSe and D2D communication technologies, and the like). In theinstant case, the communications between the vehicle 100 and theinfrastructure 120 may be performed using at least one sidelink channelestablished between the vehicle 100 and the infrastructure 120.

The V2P communications may include communications between the firstvehicle 100 (e.g., the communication node located in the vehicle 100)and a person 130 (e.g., a communication node carried by the person 130).The driving information of the first vehicle 100 and movementinformation of the person 130 such as velocity, heading, time, position,and the like may be exchanged between the vehicle 100 and the person 130through the V2P communications. The communication node located in thevehicle 100 or the communication node carried by the person 130 may beconfigured to generate an alarm indicating a danger by judging adangerous situation based on the obtained driving information andmovement information. The V2P communications supported in the cellularcommunication system 140 may be performed based on sidelinkcommunication technologies (e.g., ProSe and D2D communicationtechnologies, and the like). In the instant case, the communicationsbetween the communication node located in the vehicle 100 and thecommunication node carried by the person 130 may be performed using atleast one sidelink channel established between the communication nodes.

The V2N communications may be communications between the first vehicle100 (e.g., the communication node located in the vehicle 100) and aserver connected through the cellular communication system 140. The V2Ncommunications may be performed based on the 4G communication technology(e.g., LTE or LTE-A) or the 5G communication technology (e.g., NR).Also, the V2N communications may be performed based on a Wireless Accessin Vehicular Environments (WAVE) communication technology or a WirelessLocal Area Network (WLAN) communication technology which is defined inInstitute of Electrical and Electronics Engineers (IEEE) 802.11, or aWireless Personal Area Network (WPAN) communication technology definedin IEEE 802.15.

Meanwhile, the cellular communication system 140 supporting the V2Xcommunications may be configured as follows.

FIG. 2 is a conceptual diagram illustrating an exemplary embodiment of acellular communication system.

As shown in FIG. 2 , a cellular communication system may include anaccess network, a core network, and the like. The access network mayinclude a base station 210, a relay 220, User Equipments (UEs) 231through 236, and the like. The UEs 231 through 236 may includecommunication nodes located in the vehicles 100 and 110 of FIG. 1 , thecommunication node located in the infrastructure 120 of FIG. 1 , thecommunication node carried by the person 130 of FIG. 1 , and the like.When the cellular communication system supports the 4G communicationtechnology, the core network may include a serving gateway (S-GW) 250, apacket data network (PDN) gateway (P-GW) 260, a mobility managemententity (MME) 270, and the like.

When the cellular communication system supports the 5G communicationtechnology, the core network may include a user plane function (UPF)250, a session management function (SMF) 260, an access and mobilitymanagement function (AMF) 270, and the like. Alternatively, when thecellular communication system operates in a Non-Stand Alone (NSA) mode,the core network constituted by the S-GW 250, the P-GW 260, and the MME270 may support the 5G communication technology as well as the 4Gcommunication technology, and the core network constituted by the UPF250, the SMF 260, and the AMF 270 may support the 4G communicationtechnology as well as the 5G communication technology.

Furthermore, when the cellular communication system supports a networkslicing technique, the core network may be divided into a plurality oflogical network slices. For example, a network slice supporting V2Xcommunications (e.g., a V2V network slice, a V2I network slice, a V2Pnetwork slice, a V2N network slice, etc.) may be configured, and the V2Xcommunications may be supported through the V2X network slice configuredin the core network.

The communication nodes (e.g., base station, relay, UE, S-GW, P-GW, MME,UPF, SMF, AMF, etc.) including the cellular communication system mayperform communications by use of at least one communication technologyamong a Code Division Multiple Access (CDMA) technology, a Time DivisionMultiple Access (TDMA) technology, a frequency division multiple access(FDMA) technology, an orthogonal frequency division multiplexing (OFDM)technology, a filtered OFDM technology, an orthogonal frequency divisionmultiple access (OFDMA) technology, a single carrier FDMA (SC-FDMA)technology, a non-orthogonal multiple access (NOMA) technology, ageneralized frequency division multiplexing (GFDM) technology, a filterbank multi-carrier (FBMC) technology, a universal filtered multi-carrier(UFMC) technology, and a space division multiple access (SDMA)technology.

The communication nodes (e.g., base station, relay, UE, S-GW, P-GW, MME,UPF, SMF, AMF, etc.) including the cellular communication system may beconfigured as follows.

FIG. 3 is a conceptual diagram illustrating an exemplary embodiment of acommunication node forming a cellular communication system.

As shown in FIG. 3 , a communication node 300 may include at least oneprocessor 310, a memory 320, and a transceiver 330 connected to anetwork for performing communications. Also, the communication node 300may further include an input interface device 340, an output interfacedevice 350, a storage device 360, and the like. Each component includedin the communication node 300 may communicate with each other asconnected through a bus 370.

However, each of the components included in the communication node 300may be connected to the processor 310 via a separate interface or aseparate bus rather than the common bus 370. For example, the processor310 may be connected to at least one of the memory 320, the transceiver330, the input interface device 340, the output interface device 350,and the storage device 360 via a dedicated interface.

The processor 310 may execute at least one instruction stored in atleast one of the memory 320 and the storage device 360. The processor310 may refer to a central processing unit (CPU), a graphics processingunit (GPU), or a dedicated processor on which methods in accordance withembodiments of the present disclosure are performed. Each of the memory320 and the storage device 360 may include at least one of a volatilestorage medium and a non-volatile storage medium. For example, thememory 320 may include at least one of read-only memory (ROM) and randomaccess memory (RAM).

Referring again to FIG. 2 , in the communication system, the basestation 210 may form a macro cell or a small cell, and may be connectedto the core network via an ideal backhaul or a non-ideal backhaul. Thebase station 210 may transmit signals received from the core network tothe UEs 231 through 236 and the relay 220, and may transmit signalsreceived from the UEs 231 through 236 and the relay 220 to the corenetwork. The UEs 231, 232, 234, 235 and 236 may belong to cell coverageof the base station 210. The UEs 231, 232, 234, 235 and 236 may beconnected to the base station 210 by performing a connectionestablishment procedure with the base station 210. The UEs 231, 232,234, 235 and 236 may communicate with the base station 210 after beingconnected to the base station 210.

The relay 220 may be connected to the base station 210 and may relaycommunications between the base station 210 and the UEs 233 and 234.That is, the relay 220 may transmit signals received from the basestation 210 to the UEs 233 and 234, and may transmit signals receivedfrom the UEs 233 and 234 to the base station 210. The UE 234 may belongto both of the cell coverage of the base station 210 and the cellcoverage of the relay 220, and the UE 233 may belong to the cellcoverage of the relay 220. That is, the UE 233 may be located outsidethe cell coverage of the base station 210. The UEs 233 and 234 may beconnected to the relay 220 by performing a connection establishmentprocedure with the relay 220. The UEs 233 and 234 may communicate withthe relay 220 after being connected to the relay 220.

The base station 210 and the relay 220 may support multiple-input,multiple-output (MIMO) technologies (e.g., single user (SU)-MIMO,multi-user (MU)-MIMO, massive MIMO, etc.), coordinated multipoint (CoMP)communication technologies, carrier aggregation (CA) communicationtechnologies, unlicensed band communication technologies (e.g., LicensedAssisted Access (LAA), enhanced LAA (eLAA), etc.), sidelinkcommunication technologies (e.g., ProSe communication technology, D2Dcommunication technology), or the like. The UEs 231, 232, 235 and 236may perform operations corresponding to the base station 210 andoperations supported by the base station 210. The UEs 233 and 234 mayperform operations corresponding to the relays 220 and operationssupported by the relays 220.

Here, the base station 210 may be referred to as a Node B (NB), anevolved Node B (eNB), a base transceiver station (BTS), a radio remotehead (RRH), a transmission reception point (TRP), a radio unit (RU), aroadside unit (RSU), a radio transceiver, an access point, an accessnode, or the like. The relay 220 may be referred to as a small basestation, a relay node, or the like. Each of the UEs 231 through 236 maybe referred to as a terminal, an access terminal, a mobile terminal, astation, a subscriber station, a mobile station, a portable subscriberstation, a node, a device, an on-broad unit (OBU), or the like.

Meanwhile, the communications between the UEs 235 and 236 may beperformed based on the sidelink communication technique. The sidelinkcommunications may be performed based on a one-to-one scheme or aone-to-many scheme. When V2V communications are performed using thesidelink communication technique, the UE 235 may be the communicationnode located in the first vehicle 100 of FIG. 1 and the UE 236 may bethe communication node located in the second vehicle 110 of FIG. 1 .When V2I communications are performed using the sidelink communicationtechnique, the UE 235 may be the communication node located in firstvehicle 100 of FIG. 1 and the UE 236 may be the communication nodelocated in the infrastructure 120 of FIG. 1 . When V2P communicationsare performed using the sidelink communication technique, the UE 235 maybe the communication node located in first vehicle 100 of FIG. 1 and theUE 236 may be the communication node carried by the person 130 of FIG. 1.

The scenarios to which the sidelink communications are applied may beclassified as shown below in Table 1 according to the positions of theUEs (e.g., the UEs 235 and 236) participating in the sidelinkcommunications. For example, the scenario for the sidelinkcommunications between the UEs 235 and 236 shown in FIG. 2 may be asidelink communication scenario C.

TABLE 1 Sidelink Communication Position Position Scenario of UE 235 ofUE 236 A Out of coverage of Out of coverage of base station 210 basestation 210 B In coverage of base Out of coverage of base station 210station 210 C In coverage of base In coverage of base station 210station 210 D In coverage of base In coverage of other station 210 basestation

Meanwhile, a user plane protocol stack of the UEs (e.g., the UEs 235 and236) performing sidelink communications may be configured as follows.

FIG. 4 is a block diagram illustrating an exemplary embodiment of a userplane protocol stack of a UE performing sidelink communication.

As shown in FIG. 4 , a left UE may be the UE 235 shown in FIG. 2 and aright UE may be the UE 236 shown in FIG. 2 . The scenario for thesidelink communications between the UEs 235 and 236 may be one of thesidelink communication scenarios A through D of Table 1. The user planeprotocol stack of each of the UEs 235 and 236 may include a physical(PHY) layer, a medium access control (MAC) layer, a radio link control(RLC) layer, and a packet data convergence protocol (PDCP) layer.

The sidelink communications between the UEs 235 and 236 may be performedusing a PC5 interface (e.g., PC5-U interface). A layer-2 identifier (ID)(e.g., a source layer-2 ID, a destination layer-2 ID) may be used forthe sidelink communications, and the layer 2-ID may be an ID configuredfor the V2X communications (e.g., V2X service). Also, in the sidelinkcommunications, a hybrid automatic repeat request (HARQ) feedbackoperation may be supported, and an RLC acknowledged mode (RLC AM) or anRLC unacknowledged mode (RLC UM) may be supported.

Meanwhile, a control plane protocol stack of the UEs (e.g., the UEs 235and 236) performing sidelink communications may be configured asfollows.

FIG. 5 is a block diagram illustrating a first exemplary embodiment of acontrol plane protocol stack of a UE performing sidelink communication,and FIG. 6 is a block diagram illustrating a second exemplary embodimentof a control plane protocol stack of a UE performing sidelinkcommunication.

As shown in FIG. 5 and FIG. 6 , a left UE may be the UE 235 shown inFIG. 2 and a right UE may be the UE 236 shown in FIG. 2 . The scenariofor the sidelink communications between the UEs 235 and 236 may be oneof the sidelink communication scenarios A through D of Table 1. Thecontrol plane protocol stack illustrated in FIG. 5 may be a controlplane protocol stack for transmission and reception of broadcastinformation (e.g., Physical Sidelink Broadcast Channel (PSBCH)).

The control plane protocol stack shown in FIG. 5 may include a PHYlayer, a MAC layer, an RLC layer, and a radio resource control (RRC)layer. The sidelink communications between the UEs 235 and 236 may beperformed using a PC5 interface (e.g., PC5-C interface). The controlplane protocol stack shown in FIG. 6 may be a control plane protocolstack for one-to-one sidelink communication. The control plane protocolstack shown in FIG. 6 may include a PHY layer, a MAC layer, an RLClayer, a PDCP layer, and a PC5 signaling protocol layer.

Meanwhile, channels used in the sidelink communications between the UEs235 and 236 may include a Physical Sidelink Shared Channel (PSSCH), aPhysical Sidelink Control Channel (PSCCH), a Physical Sidelink DiscoveryChannel (PSDCH), and a Physical Sidelink Broadcast Channel (PSBCH). ThePSSCH may be used for transmitting and receiving sidelink data and maybe configured in the UE (e.g., UE 235 or 236) by a higher layersignaling. The PSCCH may be used for transmitting and receiving sidelinkcontrol information (SCI) and may also be configured in the UE (e.g., UE235 or 236) by a higher layer signaling.

The PSDCH may be used for a discovery procedure. For example, adiscovery signal may be transmitted over the PSDCH. The PSBCH may beused for transmitting and receiving broadcast information (e.g., systeminformation). Also, a demodulation reference signal (DM-RS), asynchronization signal, or the like may be used in the sidelinkcommunications between the UEs 235 and 236. The synchronization signalmay include a primary sidelink synchronization signal (PSSS) and asecondary sidelink synchronization signal (SSSS).

Meanwhile, a sidelink transmission mode (TM) may be classified intosidelink

TMs 1 to 4 as shown below in Table 2.

TABLE 2 Sidelink TM Description 1 Transmission using resources scheduledby base station 2 UE autonomous transmission without scheduling of basestation 3 Transmission using resources scheduled by base station in V2Xcommunications 4 UE autonomous transmission without scheduling of basestation in V2X communications

When the sidelink TM 3 or 4 is supported, each of the UEs 235 and 236may perform sidelink communications using a resource pool configured bythe base station 210. The resource pool may be configured for each ofthe sidelink control information and the sidelink data.

The resource pool for the sidelink control information may be configuredbased on an RRC signaling procedure (e.g., a dedicated RRC signalingprocedure, a broadcast RRC signaling procedure). The resource pool usedfor reception of the sidelink control information may be configured by abroadcast RRC signaling procedure. When the sidelink TM 3 is supported,the resource pool used for transmission of the sidelink controlinformation may be configured by a dedicated RRC signaling procedure. Inthe instant case, the sidelink control information may be transmittedthrough resources scheduled by the base station 210 within the resourcepool configured by the dedicated RRC signaling procedure. When thesidelink TM 4 is supported, the resource pool used for transmission ofthe sidelink control information may be configured by a dedicated RRCsignaling procedure or a broadcast RRC signaling procedure. In theinstant case, the sidelink control information may be transmittedthrough resources selected autonomously by the UE (e.g., UE 235 or 236)within the resource pool configured by the dedicated RRC signalingprocedure or the broadcast RRC signaling procedure.

When the sidelink TM 3 is supported, the resource pool for transmittingand receiving sidelink data may not be configured. In the instant case,the sidelink data may be transmitted and received through resourcesscheduled by the base station 210. When the sidelink TM 4 is supported,the resource pool for transmitting and receiving sidelink data may beconfigured by a dedicated RRC signaling procedure or a broadcast RRCsignaling procedure. In the instant case, the sidelink data may betransmitted and received through resources selected autonomously by theUE (e.g., UE 235 or 236) within the resource pool configured by thededicated RRC signaling procedure or the broadcast RRC signalingprocedure.

Hereinafter, sidelink communication methods will be described. Even whena method (e.g., transmission or reception of a signal) to be performedat a first communication node among communication nodes is described, acorresponding second communication node may perform a method (e.g.,reception or transmission of the signal) corresponding to the methodperformed at the first communication node. That is, when an operation ofa UE #1 (e.g., vehicle #1) is described, a UE #2 (e.g., vehicle #2)corresponding thereto may perform an operation corresponding to theoperation of the UE #1. Conversely, when an operation of the UE #2 isdescribed, the corresponding UE #1 may perform an operationcorresponding to the operation of the UE #2. In exemplary embodimentsdescribed below, an operation of a vehicle may be an operation of acommunication node located in the vehicle.

In exemplary embodiments of the present disclosure, signaling may be oneor a combination of two or more of higher layer signaling, MACsignaling, and physical (PHY) signaling. A message used for higher layersignaling may be referred to as a ‘higher layer message’ or ‘higherlayer signaling message’. A message used for MAC signaling may bereferred to as a ‘MAC message’ or ‘MAC signaling message’. A messageused for PHY signaling may be referred to as a ‘PHY message’ or ‘PHYsignaling message’. The higher layer signaling may refer to an operationof transmitting and receiving system information (e.g., masterinformation block (MIB), system information block (SIB)) and/or an RRCmessage. The MAC signaling may refer to an operation of transmitting andreceiving a MAC control element (CE). The PHY signaling may refer to anoperation of transmitting and receiving control information (e.g.,downlink control information (DCI), uplink control information (UCI), orSCI).

A sidelink signal may be a synchronization signal and a reference signalused for sidelink communication. For example, the synchronization signalmay be a synchronization signal/physical broadcast channel (SS/PBCH)block, sidelink synchronization signal (SLSS), primary sidelinksynchronization signal (PSSS), secondary sidelink synchronization signal(SSSS), or the like. The reference signal may be a channel stateinformation-reference signal (CSI-RS), DM-RS, phase tracking-referencesignal (PT-RS), cell-specific reference signal (CRS), sounding referencesignal (SRS), discovery reference signal (DRS), or the like.

A sidelink channel may be a PSSCH, PSCCH, PSDCH, PSBCH, physicalsidelink feedback channel (PSFCH), or the like. Furthermore, a sidelinkchannel may refer to a sidelink channel including a sidelink signalmapped to specific resources in the corresponding sidelink channel. Thesidelink communication may support a broadcast service, a multicastservice, a groupcast service, and a unicast service.

The sidelink communication may be performed based on a single-SCI schemeor a multi-SCI scheme. When the single-SCI scheme is used, datatransmission (e.g., sidelink data transmission, sidelink-shared channel(SL-SCH) transmission) may be performed based on one SCI (e.g.,1st-stage SCI). When the multi-SCI scheme is used, data transmission maybe performed using two SCIs (e.g., 1st-stage SCI and 2nd-stage SCI).

The SCI(s) may be transmitted on a PSCCH and/or a PSSCH. When thesingle-SCI scheme is used, the SCI (e.g., 1st-stage SCI) may betransmitted on a PSCCH. When the multi-SCI scheme is used, the 1st-stageSCI may be transmitted on a PSCCH, and the 2nd-stage SCI may betransmitted on the PSCCH or a PSSCH. The 1st-stage SCI may be referredto as ‘first-stage SCI’, and the 2nd-stage SCI may be referred to as‘second-stage SCI’. A format of the first-stage SCI may include a SCIformat 1-A, and a format of the second-stage SCI may include a SCIformat 2-A and a SCI format 2-B.

The 1st-stage SCI may include or more information elements amongpriority information, frequency resource assignment information, timeresource assignment information, resource reservation periodinformation, demodulation reference signal (DMRS) pattern information,2nd-stage SCI format information, a beta offset indicator, the number ofDMRS ports, and modulation and coding scheme (MCS) information. The2nd-stage SCI may include one or more information elements among a HARQprocessor identifier (ID), a redundancy version (RV), a source ID, adestination ID, CSI request information, a zone ID, and communicationrange requirements.

Meanwhile, a receiving terminal may operate in an RRC inactive mode, RRCidle mode, or sleep mode. When data (e.g., sidelink data) to betransmitted to the receiving terminal exists in a transmitting terminal,the transmitting terminal may transmit a paging message and/or a wake-upsignal to the receiving terminal to inform that the data exists. Thereceiving terminal may receive the paging message and/or the wake-upsignal from the transmitting terminal. The receiving terminal may beconfigured to determine that the data to be transmitted to the receivingterminal exists in the transmitting terminal based on informationincluded in the paging message and/or the wake-up signal.

In the instant case, the operation state of the receiving terminal maytransition to an RRC connected state. The receiving terminal operatingin the RRC connected state may receive the data from the transmittingterminal. The above-described operations may be performed using sidelinkresources configured according to a resource allocation (RA) mode 2. Inexemplary embodiments of the present disclosure, the transmittingterminal may refer to a terminal transmitting data, the receivingterminal may refer to a terminal receiving the data, and the receivingterminal may be interpreted as ‘one or more receiving terminals’.Methods for transmitting and receiving a paging message will bedescribed in the following exemplary embodiments of the presentdisclosure. The methods for transmitting and receiving a paging messagemay be applied identically or similarly to transmission and reception ofa wake-up signal. That is, in the exemplary embodiments of the presentdisclosure, a paging message may be interpreted as a wake-up signal. Apaging message may be used as a meaning including a wake-up signal. Forexample, a paging message may include a wake-up signal.

Exemplary Embodiment 1

A window in which a resource sensing operation for transmission of apaging message is performed (hereinafter referred to as ‘A window’), awindow in which a resource selection operation for transmission of thepaging message and a resource sensing operation for transmission of data(e.g., data associated with the paging message) are performed(hereinafter referred to as ‘B window’), and a window in which aresource selection operation for transmission of the data is performed(hereinafter referred to as ‘C window’) may be independently configured.

FIG. 7 is a sequence chart illustrating a first exemplary embodiment ofa method for transmitting and receiving data according to a pagingprocedure in sidelink communication.

As shown in Table 7, a data transmission/reception method according to apaging procedure may include four steps (e.g., step S701, step S702,step S703, and step S704). As a previous step of the four steps, atransmitting terminal and/or a receiving terminal may receive windowconfiguration information from a base station. The window configurationinformation may include configuration information of an A window,configuration information of a B window, and/or configurationinformation of a C window. The window configuration information may beconfigured using at least one of system information, an RRC message, aMAC control element (CE), or control information (e.g., downlink controlinformation (DCI)).

When there is data to be transmitted to the receiving terminal, thetransmitting terminal may perform a transmission operation of a pagingmessage. For example, the transmitting terminal may perform a resourcesensing operation within the A window (S701). The transmitting terminalmay be configured to determine (e.g., detect or sense) paging (P)candidate resource(s) by performing the resource sensing operation. Thetransmitting terminal may select a P transmission resource from amongthe P candidate resource(s) within the B window, and may transmit apaging message in the selected P transmission resource (S702). Thereceiving terminal may receive the paging message from the transmittingterminal, and may be configured to determine that data exists in thetransmitting terminal based on information included in the pagingmessage. In the instant case, an operation state of the receivingterminal may transition from an RRC inactive mode, RRC idle mode, orsleep mode to an RRC connected mode.

After transmitting the paging message, the transmitting terminal mayperform a resource sensing operation for data transmission within the Bwindow (S703). That is, both the resource selection operation fortransmission of the paging message and the resource sensing operationfor data transmission may be performed within the B window. The pagingmessage may be transmitted to indicate the existence of the data. Thedata in the step S703 may be associated with the paging message in thesteps S701 and S702. The transmitting terminal may be configured todetermine (e.g., detect or sense) data (D) candidate resource(s) byperforming the resource sensing operation. The transmitting terminal mayselect a D transmission resource from among the D candidate resource(s)within the C window, and may transmit the data (e.g., sidelink data) inthe selected D transmission resource (S704). The receiving terminal mayreceive the data from the transmitting terminal.

The above-described four steps may be performed as follows. In the stepS701, when data to be transmitted to the receiving terminal occurs, theA window may be started. The transmitting terminal may detect usableresource(s) (e.g., P candidate resource(s)) by performing the resourcesensing operation within the A window. In the step S702, the B windowmay be configured, and the transmitting terminal may select the Ptransmission resource from among the P candidate resource(s) within theB window, and may transmit the paging message using the P transmissionresource.

The receiving terminal may receive the paging message from thetransmitting terminal by performing a monitoring operation in the Bwindow. The receiving terminal may identify that data to be transmittedto the receiving terminal exists in the transmitting terminal based onthe paging message. In the instant case, the receiving terminal mayperform a PSCCH monitoring operation to receive SCI for scheduling thedata.

In the step S703, the transmitting terminal may detect D candidateresource(s) by performing the resource sensing operation within the Bwindow. In the step S704, the C window may be configured, and thetransmitting terminal may select the D transmission resource from amongthe D candidate resource(s) within the C window, and may transmit thedata using the D transmission resource. The receiving terminal mayreceive the data from the transmitting terminal.

A time resource and/or a frequency resource of each of the A window, Bwindow, and C window may be configured within a resource pool. The Awindow, B window, and C window may be configured as follows.

FIG. 8 is a conceptual diagram illustrating a first exemplary embodimentof windows for a resource sensing operation and/or a resource selectionoperation in sidelink communication.

As shown in FIG. 8 , the A window may be configured in a time resourcefrom T1 to T2, the B window may be configured in a time resource from T3to T4, and the C window may be configured in a time resource from T5 toT6. The receiving terminal may perform a PSCCH monitoring operation froma start time (i.e., T3) of the B window. T1 to T6 may mean continuoustime or discontinuous time. Each of T1 to T6 may be expressed as atransmission time interval (TTI), symbol index, subframe index, slotindex, or mini-slot index. The symbol index may be an orthogonalfrequency division multiplexing (OFDM) symbol index, an orthogonalfrequency division multiple access (OFDMA) symbol index, a singlecarrier (SC)-frequency division multiplexing (FDM) symbol index, or asignal carrier-frequency division multiple access (SC-FDMA) symbolindex. Frequency resources of the A window, B window, and C window maybe configured to be the same or different from each other.Alternatively, the frequency resources of the A window, B window, and Cwindow may be configured to partially overlap.

A window interval (hereinafter, referred to as ‘first window interval’)between an end time (i.e., T2) of the A window and a start time (i.e.,T3) of the B window may be configured. A window interval (hereinafterreferred to as ‘second window interval’) between an end time (i.e., T4)of the B window and a start time (i.e., T5) of the C window may beconfigured. The window intervals described above may be configuredidentically or differently.

The base station may configure one or more information elements definedin Table 3 below, and may transmit the one or more information elementsto the terminal(s) (e.g., transmitting terminal and/or receivingterminal) using at least one of system information, RRC message, MAC CE,or control information. The terminal(s) may identify the one or moreinformation elements defined in Table 3 below by receiving at least oneof the system information, RRC message, MAC CE, or control informationfrom the base station. Alternatively, one or more information elementsdefined in Table 3 below may be configured by the transmitting terminal,and the transmitting terminal may transmit the one or more informationelements to the receiving terminal using at least one of an RRC message,MAC CE, or control information (e.g., SCI). The receiving terminal mayidentify the one or more information elements defined in Table 3 belowby receiving at least one of the RRC message, MAC CE, or controlinformation from the transmitting terminal.

TABLE 3 Information element(s) Time and/or frequency resourceinformation of A window Time and/or frequency resource information of Bwindow Time and/or frequency resource information of C window Firstwindow interval Second window interval

The A window, B window, and C window may be configured for each resourcepool. In exemplary embodiments of the present disclosure, the resourcepool may be referred to as ‘RP’.

TABLE 4 Resource pool A window B window C window RP #1 X1 slots X2 slotsX3 slots RP #1 X4 slots X5 slots X6 slots RP #2 X7 slots X8 slots X9slots RP #2 X10 slots  X11 slots  X12 slots 

Referring to Table 4, the A window, B window, and C window for each ofthe RP #1 and the RP #2 may be independently configured. In Table 4, theA window, B window, and C window may be configured in the same frequencyresource. When the A window, B window, and C window are configured indifferent frequency resources, Table 4 may further include frequencyresource information. In the instant case, the frequency resource may beconfigured in units of subcarriers, subchannels, or resource blocks(RBs). That is, the frequency resource may be represented by subcarrierindex(es), subchannel index(es), or RB index(es). A subchannel mayinclude one or more subcarriers or one or more RBs. The RB may be aphysical RB (PRB), a virtual RB (VRB), or a common RB (CRB). Thefrequency resource of each of the A window, B window, and C window maybe expressed as a relative location (e.g., offset) from a referenceresource within the resource pool.

When two resource pools (e.g., RP #1 and RP #2) are allocated (e.g.,configured) in the transmitting terminal, the A window, B window, and Cwindow defined in Table 4 may be configured. In Table 4, each of X1 toX12 may be a natural number. The time resource of each of the A window,B window, and C window may be indicated by the number of slots.Alternatively, the time resource of each of the A window, B window, andC window may be configured in units of TTIs, symbols, subframes,mini-slots, milliseconds, or seconds. The sizes of the time resources ofthe A window, B window, and C window may be the same or different.

Referring to Table 4, two window configurations may be configured forone resource pool. For example, according to a first windowconfiguration for the RP #1, the time resource of the A window may beconfigured in X1 slots, the time resource of the B window may beconfigured in X2 slots, and the time resource of the C window may beconfigured in X3 slots. According to a second window configuration forthe RP #1, the time resource of the A window may be configured in X4slots, the time resource of the B window may be configured in X5 slots,and the time resource of the C window may be configured in X6 slots.

When a plurality of window configurations exist for one resource pool,the transmitting terminal may use one window configuration among theplurality of window configurations according to specific condition(s).The base station may configure the specific condition(s) to thetransmitting terminal and/or the receiving terminal using at least oneof system information, RRC signaling, MAC CE, or control information.The specific condition(s) may be defined as shown in Table 5 below.

TABLE 5 Description Condition #1 Size of data to be transmitted from thetransmitting terminal to the receiving terminal (e.g., the number ofdata transmissions) Condition #2 Required latency Condition #3 Priorityper data Condition #4 Priority per sidelink service

For example, when the size of the data to be transmitted from thetransmitting terminal to the receiving terminal is greater than or equalto a threshold, the transmitting terminal may select a windowconfiguration including a large time resource from among the pluralityof window configurations for one resource pool. When a priority of thedata is high or when a required latency is short, the transmittingterminal may select a window configuration including a small timeresource from among the plurality of window configurations for oneresource pool. When transmission resources for a plurality of datatransmissions are required, the transmitting terminal may select awindow configuration including a large time resource from among theplurality of window configurations for one resource pool.

TABLE 6 Configuration value First window interval (T3-T2) Y1 Y2 Secondwindow interval (T5-T4) Y3 Y4

The window intervals shown in Table 8 may be configured as shown inTable 6. Each of Y1 to Y4 may be configured in units of TTIs, symbols,subframes, slots, mini-slots, milliseconds, or seconds. A plurality ofconfiguration values (e.g., two configuration values) may be configuredfor one window interval. In the instant case, the transmitting terminalmay use one configuration value among the plurality of configurationvalues based on the specific condition(s) defined in Table 5.Alternatively, the first window interval and the second window intervalmay have the same configuration value (e.g., time resource).

FIG. 9 is a conceptual diagram illustrating a second exemplaryembodiment of windows for a resource sensing operation and/or a resourceselection operation in sidelink communication.

As shown in FIG. 9 , the A window, B window, and/or C window may beearly terminated. The A window may be configured in a time resource fromT1 to T2, and may be early terminated at T3 before T2. For example, whenthe resource sensing operation is completed before T3, the A window maybe early terminated at T3. T3 may be used as a reference value for earlytermination of the A window. When the A window is early terminated, theB window may start from the early termination time (i.e., T3) of the Awindow, and the transmitting terminal may perform the resource selectionoperation for paging message transmission and the resource sensing fordata transmission within the

B window. Alternatively, when the first window interval is configured,the B window may be started after a time (T3+ the first windowinterval).

The B window may be configured in a time resource from T3 to T4, and maybe early terminated at a specific time before T4. For example, when theresource selection operation for paging message transmission and theresource sensing operation for data transmission are completed beforethe specific time, the B window may be early terminated at the specifictime. The specific time may be used as a reference value for earlytermination of the B window. When the B window is early terminated, theC window may be started from the early termination time (i.e., thespecific time) of the B window, and the transmitting terminal mayperform the resource selection operation within the C window.Alternatively, when the second window interval is configured, the Cwindow may be started after a time (the specific time +the second windowinterval). The above-described early termination operation of the windowmay be applied in the same or similar manner to the C window. The earlytermination time of the window may be configured as shown in Table 7below. The base station may transmit configuration information of theearly termination times to the transmitting terminal and/or thereceiving terminal using at least one of system information, RRCmessage, MAC CE, or control information.

TABLE 7 Early termination Resource A B C time of pool window windowwindow window RP #1 X1 slots X2 slots X3 slots Z1 slots RP #1 X4 slotsX5 slots X6 slots Z2 slots RP #2 X7 slots X8 slots X9 slots Z3 slots RP#2 X10 slots  X11 slots  X12 slots  Z4 slots

The transmitting terminal and/or receiving terminal may operateaccording to the configurations defined in Table 7. For example, thetransmitting terminal may perform the resource sensing operation in theA window within the RP #1. When the resource sensing operation iscompleted within (X1-Z1) slots, the transmitting terminal may terminatethe A window early, and may perform the resource selection operation forpaging message transmission and the resource sensing operation for datatransmission in the B window configured in X2 slots. When the firstwindow interval is configured, the B window may be started after thefirst window interval from the early termination time of the A window.

When the resource selection operation for paging message transmissionand the resource sensing operation for data transmission are completedwithin (X2-Z1) slots, the transmitting terminal may early terminate theB window, and may perform the resource selection operation for datatransmission in the C window configured in X3 slots. When the secondwindow interval is configured, the C window may be started after thesecond window interval from the early termination time of the B window.

The early termination operation of the window may be enabled or disabledby the base station. For example, when the base station transmitsinformation indicative of enabling the early termination operation ofthe window, the transmitting terminal may perform the early terminationoperation of the window. On the other hand, when the base stationtransmits information indicative of disabling the early terminationoperation of the window, the transmitting terminal may not perform theearly termination operation of the window. The information indicative ofenabling or disabling the early termination operation of the window maybe transmitted through at least one of system information, an RRCmessage, a MAC CE, or control information.

The early termination operation of the window may be performed whenspecific condition(s) are satisfied. The specific condition(s) may bethe specific condition(s) defined in Table 5. The specific condition(s)may be configured by at least one of system information, RRC message,MAC CE, or control information. For example, when a priority of the datais higher than a reference priority (e.g., reference priority configuredby higher layer signaling) or when a required latency is shorter than areference latency (e.g., reference latency configured by higher layersignaling), the transmitting terminal may perform the early terminationoperation of the window.

Exemplary embodiment 2

Two windows may be operated for paging message transmission and datatransmission. The two windows may be configured as follows.

Scheme 1: a window #1 in which a resource sensing operation and aresource selection operation for paging message transmission areperformed and a window #2 in which a resource sensing operation and aresource selection operation for data transmission are performed

Scheme 2: a window #1 in which a resource sensing operation for pagingmessage transmission and data transmission is performed and a window #2in which a resource selection operation for paging message transmissionand data transmission is performed

In the following exemplary embodiment of the present disclosure, awindow #1 may mean the window #1 according to Scheme 1 or Scheme 2, anda window #2 may mean the window #2 according to Scheme 1 or Scheme 2.

A time offset from a start time to an end time of the window (e.g.,window #1 and/or window #2) may be configured as shown in Table 8 below.

TABLE 8 Time offset Window #1 X Window #2 Y

The base station may transmit configuration information of the timeoffsets to the transmitting terminal and/or the receiving terminal usingat least one of system information, RRC message, MAC CE, or controlinformation. In Table 8, each of X and Y may be configured in units ofTTIs, symbols, subframes, slots, mini-slots, milliseconds, or seconds.When Scheme 1 is used, the transmitting terminal may select atransmission resource within X from a start time of the resource sensingoperation, and may transmit a paging message using the selectedtransmission resource. The above-described resource sensing operationand resource selection operation for paging message transmission may beperformed within the window #1. Furthermore, the transmitting terminalmay select a transmission resource within Y from the start time of theresource sensing operation, and may transmit data using the selectedtransmission resource. The above-described resource sensing operationand resource selection operation for data transmission may be performedwithin the window #2.

When Scheme 2 is used, the transmitting terminal may perform theresource sensing operation for paging message transmission and datatransmission within X from a start time of the window #1. Furthermore,the transmitting terminal may perform the resource selection operationfor paging message transmission and data transmission within Y from astart time of the window #2.

FIG. 10 is a conceptual diagram illustrating a third exemplaryembodiment of windows for a resource sensing operation and/or a resourceselection operation in sidelink communication.

As shown in FIG. 10 , the window #1 may be configured in a time resourcefrom T1 to T2. The time resource from T1 to T2 may be X (i.e., timeoffset) defined in Table 8. When the operations in the window #1 arecompleted before a preconfigured time (e.g., reference time or specifictime), the window #1 may be early terminated. The window #2 may beconfigured in a time resource from T3 to T4. The time resource from T3to T4 may be Y (i.e., time offset) defined in Table 8. In Scheme 1, thereceiving terminal may perform a PSCCH monitoring operation from T3 whena paging message is received within the window #1. When the operationsin the window #2 are completed before a preconfigured time (e.g.,reference time or specific time), the window #2 may be terminated early.

The time offset of the window #1 may be configured to be equal to thetime offset of the window #2. In the instant case, a single time offset(e.g., common time offset) may be used for the window #1 and the window#2. A plurality of time offsets may be configured for each of the window#1 and the window #2. In the instant case, the transmitting terminal mayselect one time offset from among the plurality of time offsets based onspecific condition(s) and may use the selected one time offset. Thespecific condition(s) may be the specific condition(s) defined in Table5. The specific condition(s) may be configured by at least one of systeminformation, RRC message, MAC CE, or control information.

FIG. 11 is a conceptual diagram illustrating a fourth exemplaryembodiment of windows for a resource sensing operation and/or a resourceselection operation in sidelink communication.

As shown in FIG. 11 , the window #1 may be configured in a time resourcefrom T1 to T2. When the operations in the window #1 are completed beforeT3, the window #1 may be early terminated at T3. The window #2 may bestarted from the early termination time (i.e., T3) of the window #1.Alternatively, the window #2 may be started after a preconfigured windowinterval from the early termination time (i.e., T3) of the window #1. InScheme 1, the receiving terminal may perform a PSCCH monitoringoperation from T3 when a paging message is received. The PSCCHmonitoring operation may be performed immediately after receiving thepaging message.

The reference time (e.g., T3) at which the early termination operationof the window is triggered may be preconfigured. The base station mayinform the reference time for the early termination operation of thewindow to the transmitting terminal and/or the receiving terminal usingat least one of system information, RRC message, MAC CE, or controlinformation. When the operations in the window #1 are not completedwithin the reference time, the transmitting terminal may not earlyterminate the window #1. When the operations in the window #1 arecompleted within the reference time, the transmitting terminal may earlyterminate the window #1.

On the other hand, in Scheme 1 of the exemplary embodiment 2, when theresource sensing operation is not completed until a specific time, thewindow may be initialized. Furthermore, in Scheme 2 of the exemplaryembodiment 2, when the resource sensing operation and/or the resourceselection operation are not completed until a specific time, the windowmay be initialized. An initialization offset for initialization of thewindow may be configured as shown in Table 9 below.

TABLE 9 Time offset Initialization offset Window #1 X F1 Window #2 Y F2

The base station may transmit configuration information of theinitialization offsets to the transmitting terminal and/or the receivingterminal using at least one of system information, RRC message, MAC CE,or control information. The initialization offset for the window #1 maybe configured independently of the initialization offset for the window#2. Alternatively, the initialization offset for the window #1 may beconfigured to be equal to the initialization offset for the window #2. Aplurality of initialization offsets may be configured for each window inone resource pool. In the instant case, the transmitting terminal mayselect one initialization offset from among the plurality ofinitialization offsets based on specific condition(s) (e.g., specificcondition(s) defined in Table 5), and may use the one initializationoffset. In Table 9, each of F1 and F2 may be configured in units ofTTIs, symbols, subframes, slots, mini-slots, milliseconds, or seconds.

FIG. 12 is a conceptual diagram illustrating a fifth exemplaryembodiment of windows for a resource sensing operation and/or a resourceselection operation in sidelink communication.

As shown in FIG. 12 , when Scheme 1 is used, the transmitting terminalmay perform the resource sensing operation and the resource selectionoperation for paging message transmission in the window #1. The window#1 may be configured in a time resource from T1 to T2. The length of thetime resource from T1 to T2 may correspond to X defined in Table 9. Theresource sensing operation may start at T1. T3 may be a time at whichthe resource sensing operation should be completed. When the resourcesensing operation is not completed within T3, the transmitting terminalmay reconfigure the window #1 based on T3. The reconfigured window #1may start at T3. A value of (T3−T1) may be F1 (i.e., initializationoffset) defined in Table 9. The length of the reconfigured window #1 maybe the same as the length of the previous window #1, and the start timeof the reconfigured window #1 may be different from the start time ofthe previous window #1. The above-described operation may be equally orsimilarly applied to the window #2.

When Scheme 2 is used, the transmitting terminal may perform theresource sensing operation for paging message transmission and theresource sensing operation for data transmission in the window #1. Theabove-described resource sensing operation(s) may start at T1. T3 may bea time at which the resource sensing operation(s) should be completed.When at least one resource sensing operation is not completed within T3,the transmitting terminal may reconfigure the window #1 based on T3. Inthe reconfigured window #1, all the resource sensing operations or atleast one resource sensing operation not completed in the previouswindow #1 may be performed. The reconfigured window #1 may start at T3.A value of (T3−T1) may be F1 (i.e., initialization offset) defined inTable 9. The length of the reconfigured window #1 may be the same as thelength of the previous window #1, and the start time of the reconfiguredwindow #1 may be different from the start time of the previous window#1. The above-described operation may be equally or similarly applied tothe window #2.

Meanwhile, in the exemplary embodiment based on Table 9 and FIG. 12 , asensing termination offset may be additionally considered. Theinitialization operation of the window may be performed after a sensingtermination offset from an end time of the resource sensing operation.The sensing termination offsets may be configured as shown in Table 10below.

TABLE 10 Time Sensing termination Initialization offset offset offsetWindow #1 X X1 F1 Window #2 Y Y1 F2

The base station may transmit configuration information of the sensingtermination offsets to the transmitting terminal and/or the receivingterminal using at least one of system information, RRC message, MAC CE,or control information. The sensing terminal offset for the window #1may be configured independently of the sensing termination offset forthe window #2. Alternatively, the sensing termination offset for thewindow #1 may be configured to be equal to the sensing terminationoffset for the window #2.

A plurality of sensing termination offsets may be configured for eachwindow in one resource pool. In the instant case, the transmittingterminal may select one sensing terminal offset from among the pluralityof sensing termination offsets based on specific condition(s) (e.g.,specific condition(s) defined in Table 5), and use the one sensingtermination offset. In Table 10, each of X1 and Y1 may be configured inunits of TTIs, symbols, subframes, slots, mini-slots, milliseconds, orseconds.

FIG. 13 is a conceptual diagram illustrating a sixth exemplaryembodiment of windows for a resource sensing operation and/or a resourceselection operation in sidelink communication.

As shown in FIG. 13 , when Scheme 1 is used, the transmitting terminalmay perform the resource sensing operation and the resource selectionoperation for paging message transmission in the window #1. The window#1 may be configured in a time resource from T1 to T2. The length of thetime resource from T1 to T2 may correspond to X defined in Table 10. Theresource sensing operation may start at T1. T3 may be a time at whichthe resource sensing operation should be completed. When the resourcesensing operation is not completed within T3, the transmitting terminalmay reconfigure the window #1 based on T4, which is a time after aninitialization offset (e.g., F1 defined in Table 10) from T3. Thereconfigured window #1 may start at T4. A value of (T3−T1) may be X1(i.e., sensing termination offset) defined in Table 10, and a value of(T4−T3) may be F1 (i.e., initialization offset) defined in Table 10. Theabove-described operation may be equally or similarly applied to thewindow #2.

When Scheme 2 is used, the transmitting terminal may perform theresource sensing operation for paging message transmission and theresource sensing operation for data transmission in the window #1. Theabove-described resource sensing operation(s) may start at T1. T3 may bea time at which the resource sensing operation(s) should be completed.When at least one resource sensing operation is not completed within T3,the transmitting terminal may reconfigure the window #1 based on T4,which is a time after the initialization offset (e.g., F1 defined inTable 10) from T3. In the reconfigured window #1, all the resourcesensing operations or at least one resource sensing operation notcompleted in the previous window #1 may be performed. The reconfiguredwindow #1 may start at T4. A value of (T3−T1) may be X1 (i.e., sensingtermination offset) defined in Table 10, and a value of (T4−T3) may beF1 (i.e., initialization offset) defined in Table 10. Theabove-described operation may be equally or similarly applied to thewindow #2.

Meanwhile, in the above-described exemplary embodiments of the presentdisclosure, the configuration value (e.g., values defined in Tables 3 to10) may be expressed as an offset based on a start time of the resourcesensing operation. Alternatively, the reference time of the offset maybe a time other than the start time of the resource sensing operation(e.g., a time preconfigured by the base station). Among the valuesdefined in Tables 3 to 10, some values may be fixed values in thecommunication system, and the remaining values may be configured by atleast one of system information, RRC message, MAC CE, or controlinformation. The values defined in Tables 3 to 10 may be cell-specificinformation (e.g., common information for a plurality of terminalswithin one cell), RP-specific information (e.g., common information forone RP), or terminal-specific information. The values defined in Tables3 to 10 may be configured independently according to the resource pool,service type, priority, power saving operation state, quality of service(QoS) parameter (e.g., reliability, latency), and/or terminal type(e.g., vehicle (V)-UE or pedestrian (P)-UE). The values defined inTables 3 to 10 may be implicitly indicated based on preconfiguredparameter(s).

The exemplary embodiments of the present disclosure may be implementedas program instructions executable by a variety of computers andrecorded on a computer readable medium. The computer readable medium mayinclude a program instruction, a data file, a data structure, or acombination thereof. The program instructions recorded on the computerreadable medium may be designed and configured specifically for thepresent disclosure or may be publicly known and available to those whoare skilled in the field of computer software.

Examples of the computer readable medium may include a hardware devicesuch as ROM, RAM, and flash memory, which are specifically configured tostore and execute the program instructions. Examples of the programinstructions include machine codes made by, for example, a compiler, aswell as high-level language codes executable by a computer, using aninterpreter. The above exemplary hardware device may be configured tooperate as at least one software module to perform the exemplaryembodiments of the present disclosure, and vice versa.

While the exemplary embodiments of the present disclosure and theiradvantages have been described in detail, it should be understood thatvarious changes, substitutions and alterations may be made hereinwithout departing from the scope of the present disclosure.

For convenience in explanation and accurate definition in the appendedclaims, the terms “upper”, “lower”, “inner”, “outer”, “up”, “down”,“upwards”, “downwards”, “front”, “rear”, “back”, “inside”, “outside”,“inwardly”, “outwardly”, “interior”, “exterior”, “internal”, “external”,“forwards”, and “backwards” are used to describe features of theexemplary embodiments with reference to the positions of such featuresas displayed in the figures. It will be further understood that the term“connect” or its derivatives refer both to direct and indirectconnection.

The foregoing descriptions of specific exemplary embodiments of thepresent disclosure have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit thepresent disclosure to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteachings. The exemplary embodiments were chosen and described toexplain certain principles of the present disclosure and their practicalapplication, to enable others skilled in the art to make and utilizevarious exemplary embodiments of the present disclosure, as well asvarious alternatives and modifications thereof. It is intended that thescope of the present disclosure be defined by the Claims appended heretoand their equivalents.

What is claimed is:
 1. An method of a transmitting user equipment (UE),the method comprising: receiving window configuration information from abase station; determining paging (P) candidate resources by performing afirst resource sensing operation for transmission of a paging messagewithin an A window indicated by the window configuration information;selecting a P transmission resource from among the P candidate resourceswithin a B window indicated by the window configuration information, andperforming a second resource sensing operation for transmission of dataassociated with the paging message; and transmitting the paging messageto a receiving UE using the P transmission resource.
 2. The method ofclaim 1, further including: selecting a data (D) transmission resourcefrom among D candidate resources within a C window indicated by thewindow configuration information; and transmitting the data to thereceiving UE using the D transmission resource, wherein the D candidateresources are determined by the second resource sensing operation. 3.The method of claim 2, wherein the A window, the B window, and the Cwindow are configured independently of each other.
 4. The method ofclaim 2, wherein the window configuration information includes timeresource information of the A window, time resource information of the Bwindow, and time resource information of the C window.
 5. The method ofclaim 2, wherein a first window interval is configured between the Awindow and the B window, a second window interval is configured betweenthe B window and the C window, and time resource information of thefirst window interval and time resource information of the second windowinterval are included in the window configuration information.
 6. Themethod of claim 1, wherein the window configuration information isconfigured for each resource pool, and first window configurationinformation and second window configuration information are configuredfor one resource pool.
 7. The method of claim 6, wherein one windowconfiguration information among the first window configurationinformation and the second window configuration information is used, andthe one window configuration information is determined according to acondition based on at least one of a size of transmission data, arequired latency, a priority per data, or a priority per sidelinkservice.
 8. The method of claim 1, further including: when the firstresource sensing operation is completed before a reference timeconfigured by the base station, early terminating the A window.
 9. Themethod of claim 8, wherein the B window starts at an early terminationtime of the A window or a time after a window interval from the earlytermination time of the A window.
 10. The method of claim 8, wherein theA window is early terminated when one or more conditions are satisfied,and the one or more conditions are determined based on at least one of asize of transmission data, a required latency, a priority per data, or apriority per sidelink service.
 11. The method of claim 8, wherein whenan early termination operation of the A window is enabled by the basestation, the A window is early terminated.
 12. An method of atransmitting user equipment (UE) in a communication system, the methodcomprising: receiving window configuration information from a basestation; performing a first resource sensing operation for transmissionof a paging message and a second resource sensing operation fortransmission of data associated with the paging message within a window#1 indicated by the window configuration information; selecting a paging(P) transmission resource from P candidate resources determined by thefirst resource sensing operation within a window #2 indicated by thewindow configuration information; selecting a data (D) transmissionresource from D candidate resources determined by the second resourcesensing operation within the window #2; transmitting the paging messageto a receiving UE in the P transmission resource; and transmitting thedata to the receiving UE in the D transmission resource.
 13. The methodof claim 12, wherein when the first resource sensing operation and thesecond resource sensing operation are completed before a first referencetime configured by the base station, the window #1 is terminated early.14. The method of claim 13, wherein the window #2 starts at an earlytermination time of the window #1 or a time after a window interval fromthe early termination time of the window #1.
 15. The method of claim 13,wherein the window #1 is early terminated when one or more conditionsare satisfied, and the one or more conditions are determined based on atleast one of a size of transmission data, a required latency, a priorityper data, or a priority per sidelink service.
 16. The method of claim13, wherein when at least one operation of the first resource sensingoperation and the second resource sensing operation is not completedwithin a second reference time configured by the base station, thewindow #1 is reconfigured, and the at least one operation is performedwithin the reconfigured window #1.
 17. The method of claim 16, whereinthe reconfigured window #1 starts from the second reference time or atime after an offset configured by the base station from the secondreference time.
 18. The method of claim 12, wherein the windowconfiguration information includes time resource information of thewindow #1 and time resource information of the window #2, and the window#1 and the window #2 are configured independently of each other.
 19. Themethod of claim 12, wherein the window configuration information isconfigured for each resource pool, and first window configurationinformation and second window configuration information are configuredfor one resource pool.
 20. The method of claim 19, wherein one windowconfiguration information among the first window configurationinformation and the second window configuration information is used, andthe one window configuration information is determined according to acondition based on at least one of a size of transmission data, arequired latency, a priority per data, or a priority per sidelinkservice.